The alcoholic-cancer link: Even one drink a day could be risky

Alcohol-related cancer may seem like something that would affect only heavy drinkers, but according to a new study, having even one drink per day can put you at risk for cancer.

Researchers from the National Cancer Institute found that alcohol-related cancer accounted for 3.5 percent of all cancer deaths in the United States in 2009 -- and even light and moderate drinkers were at significant risk.

The link between cancer and alcohol consumption has been established by previous studies, but this new study quantifies the risk, death rates, and years of life lost in a way previously unseen.

Approximately 560,000 people died from cancer in 2009, the year for which the researchers analyzed alcohol-related cancer death rates. Of those deaths, nearly 20,000 were caused by alcohol-linked cancers, according to the study, published in the American Journal of Public Health.

"People talk about how to prevent cancer, and about avoiding tobacco and eating better, but this an issue that we think has been missed," says David Nelson MD, study author and Director of the Cancer Prevention Fellowship Program at the National Cancer Institute. "20,000 deaths is a large number." Each of those deaths accounted for approximately 18 years of potential life lost, the researchers report.

Alcohol-related cancer affected men and women equally in 2009, but with different cancers. While women with alcohol-related cancer were most likely to die from breast cancer, men were most likely to have died from oral, pharynx, larynx and esophageal cancer.

While the majority -- an estimated 54 percentage -- of these deaths occurred in people who drank more than three alcoholic drinks per day, the researchers found that, depending on the type of cancer, up to 33 percent of people who died from alcohol-related cancer had consumed only one alcoholic drink per day on average.

Alcohol as part of an unhealthy lifestyle

In the new study, alcohol-related cancers predominantly killed people who consumed 40 grams or more of alcohol per day -- approximately three drinks or more. Drinking between one and three alcoholic drinks per day was linked to 14 to 17 percent of alcohol-related cancer deaths, and one drink or less per day was responsible for between 25 and 35 percent. (If that last set of number seems large, researchers explained that the higher percentage of deaths at the lower level of alcohol consumption is due to the fact that there are more people in the one-drink-per-day category.)

While researchers are not exactly sure how alcohol may lead to cancer, it is clear that poor health habits -- not just drinking -- play a major role in cancer risk.

Cancer cells are seen on a large screen connected to a microscope at the CeBit computer fair in Hanover, Germany. (Reuters/Fabian Bimmer)

Dr. Nelson says that people who drink a lot often also have a poor diet and/or smoke, which, coupled with alcohol use, puts them at a greater risk for developing cancer.

"There are some types of alcohol-related cancer, such as oral, where there are strong relationships between alcohol and tobacco," he says. "Cancer is a complex disease, but as a general rule, it is safe to say that people who are smokers are less likely to live a healthy lifestyle."

And a healthy lifestyle is the best way to ward off cancer, regardless of whether you drink alcohol, said Eric Jacobs, PhD, strategic director of pharmacoepidemiology for the American Cancer Society, in an e-mailed statement.

"Whether or not you drink alcohol, not smoking, being physically active, and maintaining a healthy weight can greatly lower your risk of fatal cancer as well as improve your general health," Dr. Jacobs said in the statement.

Women and breast cancer: assessing the alcohol risk

The dramatic link between alcohol and breast cancer death rates raises a question: Should women limit their alcohol consumption even more than is currently recommended? Moderate drinking is currently defined by the U.S. Centers for Disease Control and Prevention as one drink per day for women and two drinks per day for men.

"There is no safe level of alcohol consumption for breast cancer," asserts David H. Jernigan PhD, associate professor in the department of health, behavior and society at the Johns Hopkins Bloomberg School of Public Health in Baltimore. "The risk begins to increase the minute you pick up a drink. Women with breast cancer in their family should think long and hard about their decision to drink."

Clifford Hudis MD, chief of the breast cancer medicine service at Memorial Sloan-Kettering Cancer Center in New York City, has a different view, saying the breast cancer risk posed by drinking is simply a part of life.

"There's no such thing as a zero-risk life," Dr. Hudis says. "Unfortunately, alcohol is a part of many people's social lives, so I think those people just need to be aware of a slightly increased risk of cancer."

Knowing your family history is key to deciding whether you should avoid alcohol over fears of breast cancer, says Freya Schnabel, MD, a professor in the department of surgery at New York University Cancer Center in New York City. You need to know what you're at risk for before you can start mitigating that risk, she says.

"People need to be thoughtful about their family history and figure out where their risks are coming from," says Dr. Schnabel. "I see a lot of people where everyone in their family has breast cancer. For them, they may want to restrict and be careful about their approach to alcohol."

How alcohol can help and hurt health

Although this new study outlines the cancer risks linked to alcohol, previous studies have indicated that there may be some benefit to moderate alcohol consumption, says Jacobs.

"While even light drinking may increase risk of some cancers, notably breast cancer, light drinking may also help lower risk of heart disease, and overall death rates do not appear to be increased in light drinkers," Jacob says.

But conflicting information on the benefits and risks of alcohol makes it difficult for consumers to understand how they should balance their consumption, says Chandini Portteus, vice president of research, evaluation, and scientific programs for Susan G. Komen for the Cure.

"I think it's confusing for an everyday consumer," says Portteus. "What we need to know more about is what the threshold is -- if there is a safe limit on alcohol consumption. We don't really understand if there is a threshold or if any alcohol consumption is a concern."

The important thing for consumers is to look at all the information available and make an educated decision on what's best for them based on all of the research, Portteus says: "We can't look at one study in isolation from the rest."

But Nelson thinks the purported benefits of alcohol consumption are overrated when compared to the risks. "Even if you took into account all the potential benefits of alcohol," he says, "it causes 10 times as many deaths as it prevents worldwide."

However, notes Jernigan, most people don't want to hear that going to the bar after work could be setting you up for cancer down the line.

"The message that alcohol could be good for you resonates so much more pleasantly than the message that alcohol can kill you," he says. "We are deeply ambivalent about alcohol because we want to enjoy it and not think about its health effects."

The most important thing, Nelson believes, is to make people understand that alcohol is a carcinogen. While it may be impossible to get people to stop drinking, making them aware of the dangers can help them make smarter decisions.

"We spend a lot of time talking about potential cancer-causing agents, but alcohol is missing from the discussion," he says. "If people really want to reduce their cancer risk, one of the things they can do is avoid alcohol."